Can We ‘Grow’ Electricity?! Group #1 ★ Can We ‘Grow’ Electricity?! Zhi Wei Ngion, Tiffany Park, Leo Siha, Amy Wan, Sherry Zhang

★ Introduction Generating power produces Pollution Global warming Lemon and potato as power sources: Clean Renewable Biodegradable

★ Physics Experiment Voltage output of lemon & potato batteries How time affects the battery’s effectiveness

★ Physics Data Presentation Experiment I day 1 day 2 lemon voltage ± 0.001V Voltage ± 0.001V 1 0.985 0.993 2 0.990 0.951 3 0.973 0.989 4 1.000 0.963 5 1.008 0.950 Average 0.991 0.969

★ Physics Data Presentation Potato Voltage ± 0.001V #1 0.808 0.743 #2 0.895 0.814 #3 0.928 0.794 #4 0.938 0.940 #5 0.992 0.857 Average 0.912 0.830

Physics ★ Conclusion Lemon batteries’ potential difference (voltage output) are relatively larger Average potential difference (voltage output) of the batteries decrease as time increases

★ Chemistry Oxidation-reduction (redox) How do lemon batteries create electricity? Oxidation-reduction (redox) These reactions involve the transfer of electrons between substances. Redox reactions release energy, and this energy can be used to do work if the reactions take place in a voltaic cell.

★ Chemistry Standard Electrode Potentials The cell potential is a measure of the difference between the two electrode potentials. The standard electrode potentials, Eo , in aqueous solutions of Cu and Al are +0.34 and –1.66 V with reference to hydrogen H. The cell voltage of the ”lemon battery” is the “difference”, U = (+0.34) – (-1.66) = 2 V.

★ Chemistry Experiment To investigate the relationship between the acidity of the lemon and its voltage output.

★ Chemistry Data Presentation Experiment II China Voltage ± 0.001 V pH ± 0.1 Thailand 1 0.961 3.0 0.948 2.8 2 0.991 2.9 0.976 3 0.505 0.517 4 0.947 5 0.964 3.3 0.955 6 Average 0.869 7 0.969 3.1 8 0.940 3.2 9 0.957 10 0.916

Chemistry ★ Data Presentation

Chemistry ★ Data Presentation

Chemistry ★ Conclusion UNABLE TO PROVE: Linear relationship between voltage and acidity The conditions of the electrodes will affect the voltage of the battery

Biology ★ Experiment To investigate the geographic origins & mass of the lemons. Also the relationship of the mass of lemon with its voltage output.

★ Biology Data Presentation Lemons from the USA Mass ± 0.1g Voltage pH ± 0.1 1 164.13 g 0.907 3.0 2 179.75 g 0.946 2.9 3 155.31 g 0.914 4 173.60 g 0.906 Average 168.20 g 0.918

★ Biology Data Presentation Lemons from China Mass ± 0.1g Voltage pH ± 0.1 1 109.82 g 0.969 3.1 2 115.83 g 0.940 3.2 3 110.44 g 0.957 4 100.17 g 0.947 Average 109.07 g 0.953

Biology ★ Data Presentation

Biology ★ Data Presentation

★ Biology Conclusion Both sets of data are randomly scattered Mass does not effect the voltage output of the lemons

Conclusion and Evaluation ★ Physics Statistic values 20W light bulb 2.5 mg of coal (1 second) 2.5 kg of coal (11.5 days) cost: 2.5 RMB 108 lemons can provide the amount of voltage to power 27 LED The light energy given out by 27 LEDs equals to 120W light bulb 234 lemons can provide the amount of voltage to power 120W light bulb 108 lemons (from mainland China) cost 216 RMB

Conclusion and Evaluation ★ Physics Effectiveness of lemon batteries Individually and in groups Time factor: Lemons biodegrade Lemon battery Voltage ± 0.1V Series of batteries 1 0.9 2.1 2 3 0.7 Total voltage 2.5

Conclusion and Evaluation ★ Chemistry Effects of electrodes on the lemon battery - Surface oxidation - Electrochemistry potential Substance Standard electrode potential Lithium ﹣3.04 Magnesium ﹣2.37 Aluminum ﹣1.66 Zinc ﹣0.76 Iron ﹣0.44 Copper ＋0.34 Silver ＋0.80

Conclusion and Evaluation ★ Chemistry Economic costs for the electrodes Effects of acid in lemon on the electrodes - Corrosion of metal Requirements for the redox reaction Must be electrically connected Could be provided by just the lemon juice Metals Cost (RMB per ton) Magnesium 15.4 thousand Aluminum 15.3 thousand Copper (electrolyze) 59.0 thousand Zinc 16.4 thousand

Conclusion and Evaluation ★ Biology Lemons can be genetically altered to become smaller in size therefore more space efficient lemons are only able to bear fruit year round when grown in mild climate Transportation of lemons Areas to mass produce lemons 1. Building Greenhouses 2. Opening more areas for plantation 3. Not enough space Effect of mass production of lemons on other plantation Use of water

Conclusion and Evaluation ★ Biology Not enough lemons  affected accuracy of data 1. Variety of sizes 2. Variety of locations Time 1. Grow lemons under different conditions (e.g. soil pH)

★ Thank You!